Interpretive Summary: Eating a variety of foods at a meal increases energy intake, and one approach to reduce food intake is to reduce food variety. However, food characteristics that constitute variety are not known. The effects of varying food characteristics to reduce food variety was assessed in laboratory and field experiments. In a laboratory experiment (Experiment 1), 31 overweight children were randomized to one of three conditions and provided five daily meals in the laboratory. Conditions were the same macaroni and cheese, similar types of macaroni and cheese, or a variety of high energy dense foods. The number of trials of motivated responding to receive more of the same food before responding ceased (habituation), a potential mechanism for the variety effect, and energy intake were measured. Results showed it took more trials to reach habituation in the VARIETY group compared to the SAME and SIMILAR groups. There were also group differences in energy consumed. The SAME and SIMILAR groups reduced their intake over time in comparison to the VARIETY group. Experiment 2 randomized 30 overweight children to conditions that provided the SAME, SIMILAR or VARIETY of high energy dense dinners along with a variety of low energy dense dinners for four weeks. Results showed differences in dinner energy intake across days, with significant decreases in energy intake for the SAME and SIMILAR but not VARIETY groups. The similarity in energy intake across the SAME and SIMILAR groups suggests that children will generalize their motivation to eat across similar characteristics of foods (types of macaroni and cheese), providing general guidelines for how to manipulate variety in clinical trials.

Technical Abstract:
Food variety is related to increased energy intake, and one approach to reduce food intake is to reduce food variety. However characteristics of foods that constitute variety are not known. The effects of varying food characteristics to reduce food variety on laboratory and usual dinner intake was assessed in laboratory and field experiments. In Experiment 1, 31 overweight children were randomized to one of three conditions and provided five daily meals in the laboratory. Conditions were the same macaroni and cheese, similar types of macaroni and cheese, or a variety of high energy dense foods. Trials to habituation, a potential mechanism for the variety effect, and energy intake were measured. Results showed differences in trials to habituation between the SAME and VARIETY groups, and significant differences in energy consumed between SAME and SIMILAR versus VARIETY. Experiment 2 randomized 30 overweight children to conditions that provided the SAME, SIMILAR or VARIETY of high energy dense dinner along with a variety of low energy dense dinners for four weeks. Results showed significant differences in dinner energy intake across days, with significant decreases in energy intake for the SAME and SIMILAR but not VARIETY groups. The similarity in energy intake across the SAME and SIMILAR groups suggests that children will generalize their motivation to eat across similar characteristics of foods (types of macaroni and cheese), providing general guidelines for how to manipulate variety in clinical trials.